The experimental work proposed is designed to investigate various aspects of metabolic behavior of normal and pathologic articular cartilage by histologic, ultrastructural, histochemical, autoradiographic, biochemical, and metabolic (radioisotopic) techniques. Experiments will be performed to assess the metabolic activities of articular chondrocytes in normal and osteoarthritic cartilage; further define the ultrastructural characteristic of normal and osteoarthritic articular cartilage; analyse the content of articular cartilage from normal and osteoarthritic tissues for degradative enzymes with special emphasis on collagenase and acid hydrolases; define the role of uridine diphosphate as a stimulator of proteoglycan synthesis in normal, lacerated, and experimentally arthritic articular tissues; determine the differential rates of synthesis of the glycosaminoglycans in normal and aging articular cartilage; perform studies to determine the effect of prostaglandins on articular cartilage; analyze the role of the synthesis and degradation of the collagen of cartilage by radioisotopic techniques; further evaluate the water binding characteristics of the matrix of articular cartilage in vivo and in vitro with special emphasis on bi- and trivalent cation effect; determine the origin and significance of subchondral cysts seen in osteoarthritic human tissue; study the biochemical and enzymatic characteristics of normal, degenerative, and chymopapain treated discs as well as discs from scoliotic spines.